Conventionally, in a computer system configured from a host computer, a storage apparatus and the like, when replacing a storage apparatus with a new storage apparatus, in order to switch the access destination of the host computer from the original storage apparatus (this is hereinafter referred to as the “migration source storage apparatus”) to the new storage apparatus (this is hereinafter referred to as the “migration destination storage apparatus”), the setting of configuring the migration destination storage apparatus as the access destination needs to be made to the host computer. Thus, it is necessary to stop the host computer for a considerable period of time, and there is a problem in that business operations must be stopped during that time.
In order to overcome the foregoing problem, conventionally, a method of using alternate path software loaded in the host computer to dynamically switch the access path of the host computer, and migrating the storage apparatus without stopping the business operations performed with the host computer is being widely used (this is hereinafter referred to as the “first method”).
Moreover, as another method, for example, PTL 1 discloses a method of providing a virtualization control device, which virtualizes a logical device in a storage apparatus and provides this to a host computer, between the host computer and the storage apparatus, and switching the virtualization target based on the virtualization control device from the logical device in the migration source storage apparatus to the logical device in the migration destination storage apparatus (this is hereinafter referred to as the “second method”), and PTL 2 and PTL 3 disclose a method of applying NPIV (N_Port_ID Virtualization) to a storage apparatus, and dynamically switching the access destination (this is hereinafter referred to as the “third method”).